Subtract month from date column

Question

I would like to subtract one month from a date column in Amazon Redshift (a fork of PostgreSQL 8.0.2).

So for each date column in a table, it will add another column date_minus_a_month.

I tried this code

Select date,date::date -interval '1 month'
from table

and received an error:

Interval values with month or year parts are not supported.

Does anyone have a solution for this?

user_1052985 · Answer

You can use datesub, although I just use dateadd for everything and use negative numbers.

eg

SELECT getdate() as right_now, dateadd(month, -1, getdate()) as last_month